Air conditioning installation for a passenger cell of a vehicle

ABSTRACT

The invention relates to an air conditioning installation for a passenger cell of a vehicle, said passenger cell having a rear area, with at least one air duct which leads to the rear area and is capable of being acted upon by air of preselectable temperature, and with at least one air outflow device connected to the air duct and arranged in the rear area. To simplify the rear area air conditioning in structural terms, with the aim of lowering the manufacturing costs, while maintaining air conditioning comfort in the rear area, the air duct has leading off from it a duct branch which is closed off by means of a second air outflow device arranged in the rear area, and at the branch point is arranged an air distribution member which allocates the air volume stream flowing in the air duct to the two air outflow devices. In this case, the air distribution member is designed in such a way that the allocation of the air volume stream takes place as a function of the “cooling” and “heating” operating modes of the air conditioning installation.

The invention relates to an air conditioning installation for apassenger cell of a vehicle, said passenger cell having a rear area,according to the preamble of patent claim 1.

In a known heating and air conditioning installation for a vehicle (DE 1077 997 C2), behind each seat back of a fore or front seat, whichtogether forwardly delimit the rear area of the passenger cell, isarranged an air distributor chamber which is connected in each case toan air duct. The two air ducts are laid on the floor of the passengercell. The air flowing in each air duct is brought to the desiredtemperature in a heat exchanger. The two heat exchangers are arranged ineach case on a door column in the front space of the passenger cell andhave additional air outlet slots for ventilating the front space.

In a likewise known air conditioning installation (DE 196 46 123 A1), anair conditioning box has arranged in it an evaporator and a heatexchanger which have an air stream generated by a blower flow throughthem in the order mentioned. In the evaporator arranged in a refrigerantcircuit, the air stream is cooled, and, in the heat exchanger arrangedin the coolant circuit of the internal combustion engine of the vehicle,the air stream is heated up again. The heat exchanger is divided intofour sectors, of which the two upper sectors are provided for heatingthe left and right half of the front space and the two lower sectors areprovided for heating the right and left half of the rear area. The twolower sectors have emanating from them two pairs of air ducts, of whichone pair leads to the left half of the rear area and one pair to theright half of the rear area. Each air duct is closed off by means of anair outflow device, of which, in each case in the left and right half ofthe rear area, one air outflow device is arranged in the foot space andthe other air outflow device is arranged in the midplane of the reararea for the direct flow of air to the rear area passengers.

The object on which the invention is based is, while maintaining thesame degree of air conditioning comfort, to simplify an air conditioninginstallation of the type initially mentioned in structural terms in therear area, in order to lower the manufacturing costs.

The object is achieved, according to the invention, by means of thefeatures of patent claim 1.

The air conditioning installation according to the invention has theadvantage that only one air duct is required for routing the air to eachhalf of the rear area, the allocation of the air-conditioned air,supplied to the rear area, to the foot space and to the midplane beingmaintained. In order to provide a pleasant space climate for the reararea passengers in spite of the air of equal temperature which flowsinto the foot space and into the midplane, there is provided in the airduct, at the branch point of the duct branch, an air distribution memberwhich implements the allocation of air to the two air outflow devices asa function of the “heating” and “cooling” operating mode of the airconditioning installation. In this case, preferably, in the “cooling”operating mode the air quantity flowing into the foot space is sharplythrottled or shut off completely and, in the “heating” operating mode,the greater air quantity is blown in via the foot space.

Advantageous embodiments of the air conditioning installation accordingto the invention, together with expedient developments and refinementsof the invention, are specified in the further patent claims.

The invention is described in more detail below by means of an exemplaryembodiment illustrated in the drawing. Thus, the drawing shows adiagrammatic illustration of an air conditioning installation for apassenger cell of a vehicle.

The air conditioning installation, reproduced only diagrammatically inthe drawing, serves for the air conditioning of a passenger cell 10 of avehicle, said passenger cell being equipped with two front or fore seatsand with a rear area or back bench seat. Instead of the rear area benchseat, a plurality of individual or double seats may also be present. Ofthe front seats, only the seat backs 11 and 12 and, of the rear areabench seat, only the seat back 13 are indicated by broken lines. Byvirtue of the arrangement of the front seats, the passenger cell 10 issubdivided into a front space 14 and a rear area 15 which are capable ofbeing air-conditioned individually by means of the air conditioninginstallation. In this case, an individual setting of the climate in theleft and the right half of the passenger cell 10, both in the frontspace 14 and in the rear area 15, is provided.

The air conditioning installation has, in a known way, an airconditioning box 16, from which air ducts 17 for ventilating the frontspace 14 and air ducts 18 for ventilating the rear area 15 emanate. Ineach case one of the two air ducts 18 is routed respectively to the leftand the right half of the rear area 15. As is known and is notillustrated any further here, the air conditioning box 16 has arrangedin it an evaporator arranged in a refrigerant circuit, a heat exchangerarranged in the cooling water circuit of the internal combustion engineof the vehicle and an air distributor which follows the heat exchangerand by which the air cooled in the evaporator and heated in the heatexchanger is distributed to the air ducts 17, 18. The air stream flowingthrough the evaporator and the heat exchanger and flowing into the airdistributor is generated by a blower which is arranged at the entranceof the air conditioning box 16 and which selectively sucks in fresh airfrom the vehicle surroundings or circulation air from the passenger celland blows it into the air conditioning box 16. For the air conditioningof the rear area 15, two air outflow devices 20, 21 are provided in eachhalf of the rear area 15, the air outflow device 20 being placed in thefoot space and the air outflow device 21 being placed in the midplanefor direct flow to the rear area passengers sitting on the rear areabench seat. The drawing illustrates the air outflow devices 21 next tothe air outflow devices 20 for the sake of simplicity. In actual fact,however, they lie in a plane running above the plane of the air outflowdevices 20. The air outflow devices 20 placed in the foot space closeoff the end of the air ducts 18 which issues in the rear area 15, whilethe air outflow devices 21 arranged in the midplane are in each casearranged at the issue end of a duct branch 19 emanating from the airduct 18. The branching off of the duct branches 15 is carried out asnear as possible to the rear area end of the air ducts 18. At eachbranch point of the duct branch 19 is arranged an air distributionmember 22 for allocating the air volume flowing in the air duct 18 tothe two air outflow devices 20, 21. Each air distribution member 22 isin this case designed in such a way that the allocation of the airvolume stream to the air outflow device 20 and the air outflow device 21takes place as a function of the “cooling” and “heating” operating modeof the air conditioning installation. The allocation of the volumestream as a function of the operating mode is in this case such that, inthe “cooling” operating mode, the air volume part stream arriving at theair outflow device 20 in the foot space is throttled very sharply toshut off almost completely. By contrast, in the “heating” operatingmode, with an increase in the magnitude of the desired temperature ofthe air conditioning air, the air volume part stream arriving at the airoutflow device 21 in the midplane is increasingly throttled.

In the exemplary embodiment described, the air distribution member 22has an air flap 23 and a pivoting drive 24 which drives the air flap 23and which brings the air flap 23 into a desired pivoting positionbetween two end positions. In the end position of the air flap 23 whichis illustrated by unbroken lines in the drawing, the duct branch 19 isclosed off completely and the entire air volume stream is supplied tothe air outflow device 20. In the end position of the air flap 23 whichis illustrated by broken lines in the drawing, the duct branch 19 isopened completely and the air supply to the air outflow device 20 in thefoot space is shut off completely. The pivoting drive 24 is designed asa servomotor which is activated by a comparator 25 used as adesired/actual-value comparator. The comparator 25 is connected on theinput side to a temperature sensor 26 and to a temperature preselectionelement 27 and compares the desired temperature value set at thetemperature preselection element 27 with the actual temperature valuedelivered by the temperature sensor 26. When the actual temperaturevalue overshoots the desired temperature value, the air conditioninginstallation will operate in its “cooling” operating mode, and thepivoting drive 24 receives an actuation signal such that it sharplythrottles the air volume part stream to the air outflow device 20 in thefoot space, that is to say transfers the air flap 23 in the direction ofthe end position indicated by broken lines in the drawing. As is notillustrated any further here, the size of the desired/actual valuedifference may be utilized in order to determine the amount ofthrottling of the air volume part stream. If, by contrast, the desiredtemperature value set by means of the temperature preselection element27 is higher than the actual temperature value delivered by thetemperature sensor 26, an opposite actuation signal is applied to thepivoting drive 24 by the comparator 25. The pivoting drive 24 thenpivots the air flap 23 in the direction of the end position illustratedby unbroken lines in the drawing, so that the air volume part streamwhich arrives at the air outflow device 21 placed in the midplane isthrottled. The size of the desired/actual value difference may beutilized, here too, for fixing the amount of throttling of the airvolume part stream arriving at the air outflow device 21.

Alternatively or additionally, the actuation signal for the pivotingdrive may be generated or modified as a function of the ventilationtemperature, so that the amount of throttling of the air volume partstreams is determined by the ventilation temperature. As is notillustrated any further, the ventilation temperature may be detecteddirectly in the air stream flowing in the air duct 18 or at anotherpoint of the air conditioning installation at which a temperatureprofile equivalent to that in the air duct 18 is present.

The invention is not restricted to the exemplary embodiment described.If an individual setting of the air conditioning in the left and theright half of the rear area 15 is dispensed with, and if there is auniform air conditioning of the rear area 15, there is, of course, noneed for a second air duct 18 with all the associated structuralelements, so that they are present only once in the setup and contextdescribed. Of course, it is possible, in each rear area half, to arrangea plurality of air outflow devices 20 in the foot space and a pluralityof air outflow devices 21 in the midplane, which are connected jointlyto the same air duct 18 or duct branch 19.

1. An air conditioning installation for a passenger cell (10) of avehicle, said passenger cell having a rear area (15), with at least oneair duct (18) which leads to the rear area (15) and which can be actedupon by air of preselectable temperature, and with at least one airoutflow device (20) which is connected to the air duct (18) and which isarranged in the rear area (15), characterized in that the air duct (18)has emanating from it a duct branch (19) which is closed off by means ofa second air outflow device (21) arranged in the rear area (15) , inthat at the branch point is arranged an air distribution member (22) forallocating the air volume flowing in the air duct (18) to the two airoutflow devices (20, 21), and in that the air distribution member (22)is designed in such a way that the allocation of the air volume streamtakes place as a function of the “cooling” and “heating” operating modesof the air conditioning installation.
 2. The air conditioninginstallation as claimed in claim 1, characterized in that one airoutflow device (20) is arranged in the foot space and the other airoutflow device (21) is arranged in the midplane of the rear area (15),and in that the allocation of the air volume stream as a function of theoperating mode is such that, in cooling operation, the air volume partstream arriving at the air outflow device (20) placed in the foot spaceis throttled.
 3. The air conditioning installation as claimed in claim2, characterized in that the allocation of the air volume stream as afunction of the operating mode is additionally such that, in heatingoperation, the air volume part stream arriving at the air outflow device(21) placed in the midplane is throttled.
 4. The air conditioninginstallation as claimed in claim 2 or 3, characterized in that theamount of throttling of the respective air volume part stream is carriedout as a function of the temperature difference between an actualtemperature and a preselected desired temperature.
 5. The airconditioning installation as claimed in one of claims 2-4, characterizedin that the amount of throttling of the respective air volume partstream is carried out as a function of a ventilation temperature.
 6. Theair conditioning installation as claimed in claim 5, characterized inthat the ventilation temperature is picked up in the air conditioninginstallation directly from the air flowing in the air duct (18) orindirectly in a temperature range equivalent to this.
 7. The airconditioning installation as claimed in one of claims 1-6, characterizedin that the air distribution member (22) has an air flap (23), which ispivotable into two end positions in each case shutting off one of theair outflow devices (20, 21), and a pivoting drive (24) which drives theair flap (23) and which can be controlled via a temperature-influencedactuation signal (27).
 8. The air conditioning installation as claimedin claim 7, characterized in that the actuation signal for the pivotingdrive (24) is formed by the output signal from a desired/actual-valuecomparator (25) which compares a desired temperature set in atemperature preselection element (27) with the actual temperaturemeasured in the rear area (15).
 9. The air conditioning installation asclaimed in claim 7 or 8, characterized in that the actuation signal forthe pivoting drive is a function of the ventilation temperature.
 10. Theair conditioning installation as claimed in one of claims 1-9,characterized in that the branch point of the duct branch (19) lies nearthe rear area end of the air duct (18).